1. Field of the Invention
The present invention relates to an improved design of a light communication device, and more particularly, to a light transmitting/receiving module having an optimal light coupling efficiency and a design for a fiber assembly thereof.
2. Description of the Related Art
In the light communication mechanism, the typical electronic signals, especially the digital electronic signals, are converted into a light signal and transmitted through the fiber. The light transmitting/receiving module of the light communication module usually uses a laser diode as a light source, and the light emitted by the light source is emitted to the fiber, such that the light signal is transmitted through the fiber. However, with the increase of the light communication load and the wide bandwidth requirement, methods of improving the light coupling efficiency of the light transmitting/receiving terminal and improving the light signal strength and the transmission distance had become the important subjects of the development.
FIG. 1 schematically shows a light transmitting/receiving terminal (also referred to as a light transmitting/receiving module hereinafter) of a light communication module in the conventional technique. As shown in FIG. 1, the light transmitting/receiving module 100 comprises a fiber assembly 110 and a laser diode 120. The fiber assembly 110 comprises a fiber 112, a ferrule 114, and a metal tube 1116. The fiber 112 comprises a core 112a and a cladding 112b, wherein the cladding 112b covers the core 112a, and the refractive index of the core 112a is greater than that of the cladding 112b. Therefore, after the light is emitted into the core 112a, the light is totally reflected on the junction of the core 112a and the cladding 112b, such that the purpose of transmitting the light signal in long distance is achieved.
Referring to FIG. 1, the end segment of the fiber 112 has a slanted end surface 130, and the ferrule 114 covers the core 112a that is disposed on the end terminal of the fiber 112 and exposes the slanted end surface 130. In addition, the metal tube 116 covering the fiber 112 and the ferrule 114 provides a protecting and positioning function. An axis of the metal tube 116 is parallel to an axis of the fiber 112. Moreover, the laser diode 120 is disposed beside the slanted end surface 130 and emits a light 140, wherein the light 140 is emitted to the slanted end surface 130 in a direction parallel to the axes of the metal tube 116 and the fiber 112, such that the light 140 is transmitted to a remote terminal through the fiber 112.
It is to be noted that since the fiber 112 has a slanted end surface 130, when the light 140 is emitted to the slanted end surface 130 in a direction parallel to the axes of the metal tube 116 and the fiber 112, it is not possible to obtain an optimal light coupling efficiency, which significantly affects the transmission performance of the light signal.
FIG. 2 schematically shows another conventional light transmitting/receiving module. Referring to FIG. 2, in the conventional light transmitting/receiving module 200, the whole set of fiber assembly 210 (including the fiber 212, the ferrule 214, and the metal tube 216) is disposed at an specific inclined angle with an outer tube 250, such that the light 240 emitted by the laser diode 220 is emitted to the slanted end surface 230 with a better incident angle, so as to improve the light coupling efficiency. However, some disadvantages still exist in the improved light transmitting/receiving module. For example, an outer tube 250 requires to be additionally added to fix the fiber assembly 210, which would increase both the size and the manufacturing cost of the light transmitting/receiving module 200.